Revert of [Tracing] Use TracingCategoryObserver in runtime statistics (patchset #6 id:140001 of https://codereview.chromium.org/2460973003/ )

Reason for revert:
Static-Initializers failed on Ubuntu-12.04

Original issue's description:
> [Tracing] Use TracingCategoryObserver in runtime statistics
>
> This patch is a follow-up patch to enable runtime statistics to use
> TracingCategoryObserver.
>
> BUG=v8:5590

TBR=cbruni@chromium.org,fmeawad@chromium.org,alph@chromium.org,bmeurer@chromium.org,mlippautz@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5590

Review-Url: https://codereview.chromium.org/2469403005
Cr-Commit-Position: refs/heads/master@{#40743}